Generally, in vehicular canister attachment structures of the above type, a drain tube extends from the canister; a joint is attached to the drain tube; the joint is attached to a body forming member comprising a floor frame, a cross-member, or the like; and an air vent hole of the canister faces the body forming member. The air vent holes of the canister protect against dust and rainwater.
A canister attachment structure in which the canister air vent holes are located around a rear fender is known, as disclosed in Japanese Patent Application Laying-Open Publication No. 9-49460 (JP 09-49460 A). The canister attachment structure disclosed in JP 09-49460 A is shown in FIG. 5 hereof.
A vehicular canister attachment structure 200 shown in FIG. 5 comprises a canister 201, an air intake and discharge path 203 that is connected to an air communication port 202 of the canister 201 and admits and discharges air, an air-intake path 204 that branches from the air intake and discharge path 203 and admits air, a canister filter (dust filter) 205 provided to a distal end of the air-intake path 204 and cleans the air, and an air-discharge path 206 that branches from the drain path 203 and discharges air.
The distal end of the air-intake path 204 is oriented upward of the vehicle body, is located at an upper portion of a rear wheel housing 208, and is open to admit air. A distal end of the air-discharge path 206 is oriented rearward of the vehicle body and is located at a lower portion of the rear wheel housing 208.
However, in the aforedescribed canister attachment structure 200, the air intake and discharge path 203 extends from the air communication port 202 of the canister 201, and the air-intake path 204 and the air-discharge path 206 branch from the path 203. Therefore, the attachment structure of the air intake and discharge path 203, the air-intake path 204, and the air-discharge path 206 becomes complex, thereby increasing the number of man-hours required for installation and increasing the cost.
In the canister attachment structure 200, it is necessary to consider measures against vapor leakage resulting from the provision of the air intake and discharge path 203, the air-intake path 204, and the air-discharge path 206.
FIGS. 6 and 7 show a vehicular canister attachment structure having a structure that is different from the canister attachment structure of Japanese Laid-open Patent Application No. 9-49460.
In FIGS. 6 and 7, a canister attachment structure 210 comprises a body forming member having a floor frame 211 and a cross-member 212 mounted on the floor frame 211. A canister 213 is attached to the cross-member 212. A canister filter 215 is additionally provided to the canister 213. A drain tube 217 has an air vent hole 216 for the canister filter 215. The drain tube 217 has a drain joint 218 connected to a distal end thereof. The drain joint 218 faces the floor frame 211. In the prior art design shown in FIG. 7, the drain joint 218 is formed with a relatively sharp bend therein, which will force any air or air-fuel mixture flowing therethrough to make at least one relatively sharp turn.
In the canister attachment structure 210, the drain tube 217 extends from the air vent hole 216 of the canister filter 215 provided to the canister 213. It is necessary to consider measures against vapor leakage and the increased number of man-hours required for installation as attributable to the extension of the drain tube 217.